While checking my catching jars after this morning's session I came across a tiny (and I mean tiny!) micro in one of them. A look through the book and horse chestnut leaf- minor looks a good bet but opinions welcomed. No records in VC49 of moths at light but several records of leafmines on horse chestnut and one record of being reared from leafmine. Apologies for pic but it's so small. If it is one they were only first discovered in London in 2002 and spread from there.